message-injector
# Message Injector
A lightweight OpenClaw workspace extension that uses the `before_agent_start` hook to inject custom text into every user message via `prependContext`.
## Installation
### 1. Create the extension directory
```bash
mkdir -p ~/.openclaw/workspace/.openclaw/extensions/message-injector
```
### 2. Copy the plugin files
Copy `scripts/index.ts` and `scripts/openclaw.plugin.json` to the extension directory:
```bash
cp scripts/index.ts ~/.openclaw/workspace/.openclaw/extensions/message-injector/
cp scripts/openclaw.plugin.json ~/.openclaw/workspace/.openclaw/extensions/message-injector/
```
### 3. Add configuration
Add the following to `~/.openclaw/openclaw.json` under `plugins.entries`:
```json
"message-injector": {
"enabled": true,
"config": {
"enabled": true,
"prependText": "Your custom text here"
}
}
```
### 4. Restart Gateway
```bash
openclaw gateway restart
```
## Configuration
| Field | Type | Default | Description |
|-------|------|---------|-------------|
| `enabled` | boolean | `true` | Enable or disable the injector |
| `prependText` | string | `""` | Text to prepend before every user message |
## Example Use Cases
**Force memory search:**
```json
"prependText": "[⚠️ 回答前必须先 memory_search 检索相关记忆，禁止凭印象回答]"
```
**Add persistent context:**
```json
"prependText": "[当前项目：my-app | 技术栈：React + Node.js | 部署环境：AWS]"
```
**Inject safety rules:**
```json
"prependText": "[RULE: Always verify file paths before deletion. Never run rm -rf without confirmation.]"
```
## How It Works
The plugin registers a `before_agent_start` hook. When triggered, it returns `{ prependContext: prependText }` which OpenClaw prepends to the user's message before the agent processes it. This is a hard injection at the Gateway level — the agent cannot skip or ignore it.
## Source Code
GitHub: https://github.com/Harukaon/openclaw-message-injector
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